remove.hpp

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#ifndef MSTL_CORE_ALGORITHM_REMOVE_HPP__
#define MSTL_CORE_ALGORITHM_REMOVE_HPP__

 
#include "MSTL/core/algorithm/search.hpp"
#include "MSTL/core/utility/reference_wrapper.hpp"
MSTL_BEGIN_NAMESPACE__


template <typename Iterator1, typename Iterator2, typename T,
    enable_if_t<is_ranges_fwd_iter_v<Iterator1> && is_ranges_fwd_iter_v<Iterator2>, int> = 0>
constexpr Iterator2 remove_copy(Iterator1 first, Iterator1 last, Iterator2 result, const T& value) {
    for (; first != last; ++first) {
        if (*first != value) {
            *result = *first;
            ++result;
        }
    }
    return result;
}

template <typename Iterator1, typename Iterator2, typename Predicate,
    enable_if_t<is_ranges_fwd_iter_v<Iterator1> && is_ranges_fwd_iter_v<Iterator2>, int> = 0>
constexpr Iterator2 remove_copy_if(Iterator1 first, Iterator1 last, Iterator2 result, Predicate pred) {
    for (; first != last; ++first) {
        if (!pred(*first)) {
            *result = *first;
            ++result;
        }
    }
    return result;
}

template <typename Iterator, typename T, enable_if_t<is_ranges_fwd_iter_v<Iterator>, int> = 0>
constexpr Iterator remove(Iterator first, Iterator last, const T& value) {
    first = _MSTL find(first, last, value);
    Iterator next = first;
    return first == last ? first : _MSTL remove_copy(++next, last, first, value);
}

template <typename Iterator, typename Predicate, enable_if_t<is_ranges_fwd_iter_v<Iterator>, int> = 0>
constexpr Iterator remove_if(Iterator first, Iterator last, Predicate pred) {
    first = _MSTL find_if(first, last, pred);
    Iterator next = first;
    return first == last ? first : _MSTL remove_copy_if(++next, last, first, pred);
}

template <typename Container, typename U>
constexpr size_t erase(Container& cont, const U& value) {
    using T = decltype(*cont.begin());
    static_assert(
        declval<T>().operator =(declval<U>()),
        "U must be comparable to the value type of Container");
 
    const auto old_size = cont.size();
    const auto end = cont.end();
    auto removed = _MSTL remove_if(cont.begin(), end,
        [&value](const auto& iter) {
            return *iter == value;
        });
    cont.erase(removed, end);
    return old_size - cont.size();
}

template <typename Container, typename Predicate>
constexpr size_t erase_if(Container& cont, Predicate pred) {
    const size_t old_size = cont.size();
    const auto end = cont.end();
    auto removed = _MSTL remove_if(cont.begin(), end,
        [ref_pred = _MSTL ref(pred)](const auto& iter) {
            return ref_pred(*iter);
        });
    cont.erase(removed, end);
    return old_size - cont.size();
}
 // RemoveAlgorithms
 
MSTL_END_NAMESPACE__
#endif // MSTL_CORE_ALGORITHM_REMOVE_HPP__